Introduction

It often happens in the field of building industry the need to monitor work-in-progress effects on the buildings near the construction area. In fact, excavations or soil handling can damage stability and structural integrity of the adjactent buildings.

Requirements

This case history tells about construction works of a touristic complex in Switzerland. To clarify: this construction area was done with the aim to build up luxury apartments in a zone of notable landscaping and environmental attractivenesses, but sub­ject also to landslides. The residential complex was to be built up in the hills, with already existing buildings nearby. So, it’s easy to imagine how security of these buildings should be kept into high consideration. What our customer needed was a monitoring system able to monitor soil stability and landslides risk for the whole area. So re­mote access to measurement data and reliable alarm transmission via e-mail or SMS were a need.

Proposal

The plant needs the use of geotechnical sensors connected to a datalogging device able to do acquisitions, storage and send alarms. Moreover, in order to measure deformation and movements of the soil, some inclinometers and solenoids were needed too. In addiction, during some critical work phases, also vibrations level has been monitored.

All sensors have been connected to the data acquisition system, in this case Next Industries’ NI2400 data logger. This device, which today is used in different applications, was developed at the beginning for geotechnical ones, and has characteristics particularly suitable for the application under consideration, including:

  • high accuracy of measurements;
  • high reliability; modern and high quality electronic, circuits tropicalisation process to suit them to outdoors installations, rugged metal case, inputs protection with discharge tubes big storage capacity; internal non-volatile 2GB memory;
  • different communication possibilities; RS-232, RS-485, Ethernet, radio-modem GSM/GPRS computing power (32 bit microcontroller ), long battery life in battery mode function thanks to adopted circuits.

NI2400 datalogger is able to supply sensor directly. This feature was fundamental for this application and it’s often not present in other devices.

As far as it concerns data transmission, collected data were sent in regular intervals to a ftp server through a GSM/GPRS modem. On the project website these data were automatically calculated and presented in chart form.

CSV data transfer

In this kind of application customers usually want to monitor data and analyze them with their own software. Through an FTP connection and with the modem NI2400 is able to send data in CSV format to a server.

Conclusions

In conclusion, monitoring project results are positive. The system has turned out to be efficient and reliable. Works could go on without any obstacle, meanwhile security of other existing building and citizenry has been guaranteed.